That carbon monoxide is deadly is widely recognized; however, so far as the general public is concerned the danger presented by this gas is associated primarily with the exhaust products of the internal combustion engine. It is widely known that the consequences of running an automobile engine in a closed garage can be fatal. Also, the public is becoming more and more aware of the fact that carbon monoxide levels resulting from heavy automobile traffic are approaching the danger point in many cities, and in some cities have already passed the danger point for substantial periods of time.
What the public has not as yet come to realize is that carbon monoxide in cigarette smoke appears to be the principal cause of death attributable to cigarette smoking. While the relationship between lung cancer and cigarette smoking, as a result of the publicity given to the results of various studies, has already penetrated mass consciousness, the fact that the carbon monoxide in cigarette smoke presents a far greater danger has not as yet reached the public consciousness. Nevertheless, medical and scientific literature as well as reports of various governmental agencies and the National Academy of Sciences are replete that data causally relating the carbon monoxide content of cigarette smoke to morbidity and death from heart disease. Indeed, the CO abosorbed from cigarette smoke by a pregnant woman has been shown to be injurious to her fetus.
It has been well-established that the carbon monoxide level in cigarette smoke can attain a level of 4 percent, or 400 parts per 10,000 parts of air. Studies have shown that where the product of hours of exposure and parts of carbon monoxide per 10,000 parts of air equals 15, a danger to life is present. On this basis, continuous inhalation of cigarette smoke with a 4 percent carbon monoxide content for longer than about 2 minutes endangers the life of a person with a normal heart. However, where the individual suffers from a circulatory deficiency, due, for example, to atherosclerosis, the danger is far greater. In other words, a fatal heart attack may ensue after smoking for a period much shorter than two minutes.
Further to the point of the danger presented by carbon monoxide, individuals exposed to this toxin as the result of being confined in a room in which the air is polluted by a multitude of smokers may also suffer serious consequences. The carbon monoxide content could also rise to dangerous levels for susceptible individuals as well as healthy individuals when travelling through automobile tunnels or when exposed to incomplete combustion products from sources such as ovens, furnaces, chemical operations, etc.
As is evident, it would be highly desirable to be able to absorb the carbon monoxide in tobacco smoke and also to be able to detect the level of carbon monoxide in the ambient atmosphere. Reduction of the carbon monoxide content in cigarette smoke would not only save many lives by way of prevention of heart attack but could also prevent the known reduction in mental acuity believed to be responsible for a substantial proportion of the automobile accidents suffered by cigarette smokers, the reduction in mental acuity being due to inhalation of carbon monoxide in substantial quantities. Further, a simple and effective carbon monoxide detector could warn of the leak of exhaust gases into the passenger compartment of an automobile, such leakage having been responsible for many accidents and deaths.
In my co-pending application having the Ser. No. 292,011, I have described the preparation of ferrous hemoglobin essentially free from methemoglobin. When employing the usual techniques, oxygen coming in contact with ferrous hemoglobin converts it to methemoglobin, so that prior attempts to manufacture hemoglobin free of methemoglobin met with failure. The difficulty was overcome by incorporating a reducing agent with the hemoglobin throughout the process and maintaining the pH of the process solutions between 6.0 and 8.5. Ascorbic acid was found to be particularly satisfactory for the purpose; it was generally found that from 2 to 8 equivalents of ascorbic acid per equivalent of hemoglobin should be used.
Unfortunately, the equivalent weight of hemoglobin is quite high, being in the neighborhood of 16,500. Consequently, the quantity of hemoglobin required to absorb a given quantity of carbon monoxide is relatively high. Some progress has been made in reducing the quantity of absorbent needed by removing part of the protein associated with the heme fraction of the hemoglobin, the rationale behind this step being the fact that it is the iron atom in the heme moiety which loses its ability to complex with oxygen as the result of the presence of carbon monoxide. However, it would be desirable to effect a further reduction in the quantity of carbon monoxide-absorbent required for reacting with a given quantity of carbon monoxide both from the standpoint of the volume occupied by the absorbent, as in a cigarette filter, and from the standpoint of cost.